The long-term goals are to develop a proteomics drug discovery platform for bone disease By focusing on primary human osteoblasts, physiologically relevant proteomic targets are discovered that are important to our understanding of bone diseases such as osteoporosis. We have successfully met milestones of the Phase I SBIR by establishing the protocol, and initial protein-map constructs for developing a human osteoblast proteomics data repository, and completing a proof-of-concept study that demonstrated osteoblast protein targets are readily identified by proteomic approaches. Further, averaged 2-DGE maps of osteoblasts protein expression that represent growth-factor specific "activation states" of these cells were generated. The specific aims of this Phase II SBIR thus focus on the transition of these proof-of-concept studies into a drug discovery tool. Aim 1 is to identify intracellular molecules and cellular pathways involved in human bone formation and incorporate these into a human osteoblast proteomics database. Its milestones are (1) examination of an additional 24 individuals per year, evaluating four different growth factor activation states in each individual (pre and post bone formation), and (2) design, implementation and population of a relational proteomics database that allows coordinate evaluation of biological, biochemical and protein image data. The second aim is to discover and confirm biomarkers of human osteoblast bone formation; Goals: (1) evaluate at least 50 proteins for their specific/common modulation during growth factor induced ex vivo human bone formation; (2) for those proteins showing a common expression characterize their ability to correctly predict the physiological state of the cell during bone formation, defining as many bone formation biomarkers as possible. The final Aim is to perform a preliminary proteomic drug discovery analysis using selected compound libraries, its milestones are to screen two small, compound libraries (selected for a predicted ability to stimulate human osteoblasts).